From: Ste on
On 2 Feb, 23:50, "J. Clarke" <jclarke.use...(a)cox.net> wrote:
> Ste wrote:
>
> > You shouldn't need *any* maths to describe in broad terms what this
> > "length contraction" is all about, and in any event anyone who
> > understands their subject should be able to sum it up in a few
> > sentences. It should not be this complex Paul, and the fact that it is
> > simply demonstrates that science has lapsed into obscuritanism.
>
> Lemme guess--you've got a degree in "education"?

I don't, but even if I did I don't see what difference it would make.
Incidentally the sort of responses you're making should be interesting
for Paul, because it reinforces what I said about how it appears any
dissent is met with ridicule and hostility.



> >> By all means, put such a scheme together. Be sure to show where the
> >> factor of 1/sqrt(1-v^2/c^2) comes from in such an explanation,
> >> because that part is quantitatively checked.
>
> > I'll let you do the maths Paul - that is, after all, the virtue of a
> > *co-operative endeavour*, where different people bring different
> > skills to the table.
>
> You are the one presenting some radical new theory which if true will set
> the Physics world on its ear and gain you the Nobel.  If you can't do the
> math then perhaps you shouldn't be pretending to be a physicist.

I'm not pretending to be a physicist - and I find it comical that you
think "reality" is a "radical new theory". I know Einstein basically
made many of the arguments that I'm making.
From: Ste on
On 3 Feb, 02:51, artful <artful...(a)hotmail.com> wrote:
> On Feb 3, 12:02 pm, Ste <ste_ro...(a)hotmail.com> wrote:
>
>
>
>
>
> > On 2 Feb, 20:10, PD <thedraperfam...(a)gmail.com> wrote:
>
> > > On Feb 2, 9:24 am, Ste <ste_ro...(a)hotmail.com> wrote:
>
> > > > But the question remains, what is the *physical* cause of the
> > > > discrepancy when the object to be measured is moving differently from
> > > > the measuring equipment. It should be a question taken seriously in
> > > > physics.
>
> > > And it is.
> > > I will give you just a sketch, meant to inspire further investigation,
> > > not to teach.
> > > The physical cause is traced to the *meaning* of the physical property
> > > length, which is the difference in the locations of the endpoints of
> > > something, where those locations are measured *simultaneously*. The
> > > importance of the simultaneity becomes apparent if you try to measure
> > > the locations of the endpoints of, say, a moving car and attribute the
> > > difference to the length. Then in turn, it becomes clear that length
> > > is frame-dependent if simultaneity is frame-dependent -- the frame-
> > > dependence of simultaneity is the physical cause of the frame-
> > > dependence of length.
>
> > Ah, now I know this is the difference between us. I hold that
> > "simultaneity" is *not* frame dependent.
>
> > > So now the question becomes, what is the
> > > physical reason for the frame-dependence of simultaneity? This in turn
> > > is traced to the *meaning* of simultaneity, and how we would know that
> > > two spatially separated events are simultaneous; this in turn hinges
> > > on the synchronous arrival of equal-speed signals from the events at
> > > the midpoint between the events. From here it is relatively simple to
> > > show that the frame-independence of the speed of light *demands* that
> > > for a given pair of events, that definition of simultaneity will be
> > > satisfied in one reference frame and not in another reference frame.
> > > That is, the frame-independence of the speed of light is the physical
> > > cause of the frame-dependence of simultaneity, which in turn is the
> > > physical cause of the frame-dependence of length. So then the question
> > > is, what is the physical cause of the frame-independence of the speed
> > > of light? The answer to this question has to do with the hyperbolic
> > > structure of space-time and the fact that causal relationships are
> > > limited to a region of spacetime called the past- and future-light
> > > cones. This hyperbolic structure of space and time is thus the
> > > physical cause of the frame-independence of the speed of light, which
> > > is in turn the physical cause of the frame-dependence of simultaneity,
> > > which in turn is the physical cause of the frame-dependence of length..
>
> > > To expand this in a way that would be compellingly easy to follow
> > > would take more pages than I'm willing to invest. Fortunately, this is
> > > done in numerous books designed to explain these things in a
> > > compellingly easy-to-follow fashion. Would you like some
> > > recommendations?
>
> > You have in fact answered the whole of my question here Paul. The
> > difference lies in our concepts of "simultaneity". As I said, my
> > concept of "simultaneous" is "those events which occur at the same
> > instant, and would be observed to do so universally, *if* information
> > about the occurence of those events could be conveyed instantaneously".
>
> Simultaneity issues in SR are nothing to do with instantly conveying
> information.
>
> According to SR your concept of simultaneity being universal does not
> hold in reality (as nice and simple and idea as it is).

I disagree. You seem to be saying that if a tree falls in the woods
and no one is around to hear it, then it didn't happen. And moreover,
the tree falls earlier for a person near to the tree than for a person
further away. But I reject these arguments. The bottom line is that
the tree falls, and it falls at the same time for all people,
regardless of whether some may observe the event later than others.
From: J. Clarke on
Ste wrote:
> On 2 Feb, 20:24, "J. Clarke" <jclarke.use...(a)cox.net> wrote:
>> Ste wrote:
>>> On 2 Feb, 16:09, "J. Clarke" <jclarke.use...(a)cox.net> wrote:
>>>> Ste wrote:
>>>>> On 1 Feb, 20:52, PD <thedraperfam...(a)gmail.com> wrote:
>>>>>> On Feb 1, 2:49 pm, kenseto <kens...(a)erinet.com> wrote:
>>
>>>>>>> So does that mean that length contraction is not physical?
>>
>>>>>> No, it does not mean that.
>>>>>> Why do you think that "observer dependent" means "not physical"?
>>>>>> Lots of physical properties are observer dependent.
>>
>>>>> Because for anyone who believes in material reality, physical
>>>>> properties should not be "observer dependent", and if physical
>>>>> properties do indeed seem to change depending on how they are
>>>>> observed, then there should be some coherent explanation for it
>>>>> rather than just a statement that things are "observer dependent",
>>>>> which in most people's minds rather leaves the glaring question
>>>>> "why".
>>
>>>> The "why" is because it is in the nature of spacetime to be that
>>>> way. Physics is decriptive.
>>
>>> Not according to Paul Draper. Apparently it is necessary that a
>>> "scientific theory" be predictive (and therefore prescriptive), not
>>> just "explanatory" (i.e. descriptive).
>>
>> It still describes, it does not address causes.
>
> Before I exclaim that "I can't believe my ears", are you saying that
> this failure to address causes is an undesirable deficiency of current
> physics, or are you saying that physics should not be concerned with
> it. If it is the former, then I think we might be in agreement, but
> not so if it is the latter.

It is the nature of science that science deals in what is observable, it
does not speculate on the unobservable. If you want to deal with "why" then
you're in the wrong shop.

>>> In any event, the question of "why" has perhaps been
>>> misinterpreted. I really meant "how". That is, what is happening in
>>> the physical system to cause a change in measurements which are
>>> "observer dependent".
>>
>> Get your PhD and work the problem for a while and maybe _you_ will
>> be the one to crack quantum gravity and collect the Nobel and come
>> up with answers to questions such as these.
>
> Lol. I prefer to leave the mathematical drudgery to someone else.

If you don't know the math anything you have to say about physics is
ignorant twaddle.

From: J. Clarke on
Ste wrote:
> On 2 Feb, 20:32, "J. Clarke" <jclarke.use...(a)cox.net> wrote:
>> Ste wrote:
>>> On 2 Feb, 15:52, PD <thedraperfam...(a)gmail.com> wrote:
>>>> On Feb 2, 9:40 am, Ste <ste_ro...(a)hotmail.com> wrote:
>>
>>>>> On 1 Feb, 20:52, PD <thedraperfam...(a)gmail.com> wrote:
>>
>>>>>> On Feb 1, 2:49 pm, kenseto <kens...(a)erinet.com> wrote:
>>
>>>>>>> So does that mean that length contraction is not physical?
>>
>>>>>> No, it does not mean that.
>>>>>> Why do you think that "observer dependent" means "not physical"?
>>>>>> Lots of physical properties are observer dependent.
>>
>>>>> Because for anyone who believes in material reality, physical
>>>>> properties should not be "observer dependent",
>>
>>>> Then I would ask the following questions of you.
>>>> Is velocity a physical property? It is *clearly*
>>>> observer-dependent.
>>
>>> Velocity is a physical property that does not vary with observer-
>>> perspective, yes. The measurement of velocity is observer-dependent,
>>> yes.
>>
>> I see. So you're the only object in an empty universe. What is your
>> velocity? How do you know that it has that value?
>
> That depends on whether the variable can be measured in an observer-
> independent fashion.

So tell us how one might measure it in an observer-independent fashion.
Tell us how your model may be falsified. If you can't then it's not
science, it's rhetoric.

>>> The discrepancy between those statements is accounted for by the
>>> fact that I believe in *material reality*, where the measurement of
>>> variables does not necessarily reflect the value of the variable
>>> itself.
>>
>> And how may your hypothesis of "material reality" be falsified? If
>> it can't then you're in the wrong shop.
>
> It can't be falsified.

Then it's not science and you're wasting everybody's time blathering about
it in science newsgroups.

> That's why I've been spending the last few
> weeks talking to Paul about how any productive endeavour involves
> axioms that are basically irrefutable.

So you're saying that all of modern engineering is not a productive
endeavor?

> And before you leap in above your pay grade and accuse me of any sort
> of subjectivity, let's talk about falsification. Why do you hold that
> falsification is necessary?

Read some Popper. It's basic to the nature of science that if your model
does not contain a means by which it may be falsified then it has no
scientific utility.

>>>> I think there may just be a clash regarding an unfounded
>>>> expectation that physical properties "should" be
>>>> observer-independent. Why would this be an expectation?
>>
>>> Oh I know that is the source of the clash. The reason I expect
>>> observer-independence is because I believe in material reality,
>>> where variables exist independent of observation or measurement.
>>
>> So measurement is meaningless? The how do you know that those
>> "variables" exist at all?
>
> Variables are inferred to exist from variance in observations.

How do you know that the variance in observations exists if you eschew
measurement?

>>>> The reality is that physics is littered with physical properties,
>>>> about which there are many laws that seem to hold remarkably well.
>>>> Some of those properties are observer-dependent, and some are
>>>> observer- independent. There is no rationale required for "why"
>>>> they are not all one way or the other, any more than there has to
>>>> be a reason cited for "why" all animals are not mammals.
>>
>>> There are no properties of the physical world that are "observer-
>>> dependent", although the measured value of those properties may
>>> depend on the circumstances of the observer.
>>
>> So you're advocating an absolute frame of reference. That's fine--if
>> you can sell that you have disproven General Relativity and you will
>> surely win the Nobel. Good luck with that.
>
> No, I'm advocating material reality. To reiterate with emphasis, there
> are no properties of the physical world that are observer-dependent,
> although the *measured value* of those properties may depend on the
> circumstances of the observer.

I see. If you can't figure out why your "material reality" requires an
absolute frame of reference then you just plain don't understand the
concept.

From: artful on
On Feb 3, 2:29 pm, Ste <ste_ro...(a)hotmail.com> wrote:
> On 3 Feb, 02:51, artful <artful...(a)hotmail.com> wrote:
>
>
>
>
>
> > On Feb 3, 12:02 pm, Ste <ste_ro...(a)hotmail.com> wrote:
>
> > > On 2 Feb, 20:10, PD <thedraperfam...(a)gmail.com> wrote:
>
> > > > On Feb 2, 9:24 am, Ste <ste_ro...(a)hotmail.com> wrote:
>
> > > > > But the question remains, what is the *physical* cause of the
> > > > > discrepancy when the object to be measured is moving differently from
> > > > > the measuring equipment. It should be a question taken seriously in
> > > > > physics.
>
> > > > And it is.
> > > > I will give you just a sketch, meant to inspire further investigation,
> > > > not to teach.
> > > > The physical cause is traced to the *meaning* of the physical property
> > > > length, which is the difference in the locations of the endpoints of
> > > > something, where those locations are measured *simultaneously*. The
> > > > importance of the simultaneity becomes apparent if you try to measure
> > > > the locations of the endpoints of, say, a moving car and attribute the
> > > > difference to the length. Then in turn, it becomes clear that length
> > > > is frame-dependent if simultaneity is frame-dependent -- the frame-
> > > > dependence of simultaneity is the physical cause of the frame-
> > > > dependence of length.
>
> > > Ah, now I know this is the difference between us. I hold that
> > > "simultaneity" is *not* frame dependent.
>
> > > > So now the question becomes, what is the
> > > > physical reason for the frame-dependence of simultaneity? This in turn
> > > > is traced to the *meaning* of simultaneity, and how we would know that
> > > > two spatially separated events are simultaneous; this in turn hinges
> > > > on the synchronous arrival of equal-speed signals from the events at
> > > > the midpoint between the events. From here it is relatively simple to
> > > > show that the frame-independence of the speed of light *demands* that
> > > > for a given pair of events, that definition of simultaneity will be
> > > > satisfied in one reference frame and not in another reference frame..
> > > > That is, the frame-independence of the speed of light is the physical
> > > > cause of the frame-dependence of simultaneity, which in turn is the
> > > > physical cause of the frame-dependence of length. So then the question
> > > > is, what is the physical cause of the frame-independence of the speed
> > > > of light? The answer to this question has to do with the hyperbolic
> > > > structure of space-time and the fact that causal relationships are
> > > > limited to a region of spacetime called the past- and future-light
> > > > cones. This hyperbolic structure of space and time is thus the
> > > > physical cause of the frame-independence of the speed of light, which
> > > > is in turn the physical cause of the frame-dependence of simultaneity,
> > > > which in turn is the physical cause of the frame-dependence of length.
>
> > > > To expand this in a way that would be compellingly easy to follow
> > > > would take more pages than I'm willing to invest. Fortunately, this is
> > > > done in numerous books designed to explain these things in a
> > > > compellingly easy-to-follow fashion. Would you like some
> > > > recommendations?
>
> > > You have in fact answered the whole of my question here Paul. The
> > > difference lies in our concepts of "simultaneity". As I said, my
> > > concept of "simultaneous" is "those events which occur at the same
> > > instant, and would be observed to do so universally, *if* information
> > > about the occurence of those events could be conveyed instantaneously".
>
> > Simultaneity issues in SR are nothing to do with instantly conveying
> > information.
>
> > According to SR your concept of simultaneity being universal does not
> > hold in reality (as nice and simple and idea as it is).
>
> I disagree. You seem to be saying that if a tree falls in the woods
> and no one is around to hear it, then it didn't happen.

How could you possibly draw that conclusion from what I wrote? It
appears you do not know what you are disagreeing with.

> And moreover,
> the tree falls earlier for a person near to the tree than for a person
> further away. But I reject these arguments.

Noone is making such arguments.

> The bottom line is that
> the tree falls, and it falls at the same time for all people,
> regardless of whether some may observe the event later than others.

SR also says if an event happens it happens for everyone, regardless
of when it is observered

You seem to be arguing against things that people here are NOT saying